This invention relates to torque converter clutch assemblies, and more particularly, to such assemblies wherein the clutch friction interface is accomplished at surfaces between the clutch pressure plate and the torque converter input shell.
Prior art torque converter and clutch assemblies incorporate a pressure plate with a friction disc bonded thereto and disposed for axial displacement for engagement with the input shell of the torque converter. The input shell of the torque converter generally has a machined surface thereon which provides the frictional interface for the friction disc and pressure plate. Due to tolerances and manufacturing methods, the alignment of the annular surface of the friction disc and the input shell is not ideal. In other words, there are imperfections such as waviness or conical configurations which prevent the frictional surfaces from providing a continuous annular engagement.
Prior art torque converter and clutch assemblies have attempted solutions to this problem including the use of an elastomer disc bonded between the friction material and the pressure plate. This solution does afford some degree of relief for the problem, however, the bonding material and the elastomer disc must be sufficiently strong to withstand the stresses present during the transmission of torque between the input shell and the pressure plate. This torque transmission results in shear forces being imposed on the elastomer disc and between the elastomer disc and its bonded surfaces. Since these shear forces can be quite large and have a detrimental affect on the elastomer material, the useful life of the clutch is shortened and/or the cost of bonding, bonding materials and elastomer materials is greatly increased.